Bush followed his veto -- his third since becoming president -- with an executive order aimed at encouraging federal agencies to support research that offers the promise of creating medically useful stem cells without destroying human embryos.

In his veto message to Congress, Bush said the legislation crossed an ethical line. "The Congress has sent me legislation that would compel American taxpayers, for the first time in our history, to support the deliberate destruction of human embryos," Bush said.

The veto came under attack from those who say the president is withholding critical support for the most promising forms of stem cell research to appease conservative Christians and other supporters who equate human embryos with human lives.

"This is just one example of how the president puts ideology before science, politics before the needs of our families -- just one more example of how out of touch with reality he and his party have become," Sen. Hillary Rodham Clinton (D-N.Y.) said during a speech to Democratic activists in Washington.

The legislation rejected by Bush would have allowed federal funding for research to study cells from donated, frozen embryos slated for destruction at fertility clinics. A new survey of 1,020 couples who have frozen embryos in storage found that 60 percent of them would be likely to donate their embryos for stem cell research. The survey, conducted by researchers at Johns Hopkins and Duke universities, was released yesterday by the journal Science.

The measure essentially would have overturned the restrictions Bush imposed shortly after he became president in 2001. It passed with large, but not veto-proof, margins in the House and the Senate.

Bush last year vetoed a similar bill seeking to expand federal funding for embryonic stem cell research. Polls show that a large majority of the public supports the research because of its potential to fight disease and save lives.

Recent advances have increased optimism that stem cells with the potential for treating diseases or even to develop into human organs for transplants can be harvested from skin cells, amniotic fluids or cells salvaged from dead embryos. During the White House ceremony, Bush pointed out an 18-year-old woman born with spina bifida who has benefited from alternative stem cell therapy that allowed her to receive a new bladder formed from cells taken from her diseased bladder.

"President Bush isn't fooling anyone with this executive order," said Sean Tipton, president of the Coalition for the Advancement of Medical Research, an advocacy group. "And the fact that it doesn't change the policy adds insult to injury for the millions of patients who suffer every day."